When President Obama gives the State of the Union address this evening, we all know one word he'll utter many times: Yes, J is for jobs.

Perhaps every successful politician promises employment. But looking back at the president's first term, where have the jobs actually come from?

Over the course of the last four years, the U.S. lost 4 million jobs, then created more than 5 million. Net gain: 1.2 million. The education and healthcare fields created many of those.

Why? We're getting older and trying to get wiser. But it also may be hard to replace workers in those fields with technology.

"Education and healthcare are two sectors where location really matters," says economist Ronnie Chatterji at Duke University. "The bedside manner of a physician, for example. Or a teacher being in the same classroom as a student."

Other sectors seeing net job gains included retail, leisure, and energy. Of course the housing market plummeted, as did jobs related to it, but that's turning up.

"In the next four years," says economist Kenneth Goldstein of the Conference Board, a business research group, "I think we'll see a return to job growth in manufacturing, in construction, and perhaps also in the public sector."

The jobless rate remains stubbornly high, at 7.9 percent. You could blame the president, or credit him for jobs created, or neither. Goldstein says in large part, market demand creates jobs.